As many as 129 million Americans under age 65 have medical problems that are red flags for health insurers, according to an analysis that marks the government's first attempt to quantify the number of people at risk of being rejected by insurance companies or paying more for coverage.

The report is part of the Obama administration's salesmanship to convince the public of the advantages of the law, which contains insurance protections for people with preexisting medical conditions.

The House's new GOP leaders plan to begin debate Tuesday on a bill that would repeal the health-care law in its entirety. The vote is set to conclude on Wednesday.

Republicans immediately disparaged the analysis as "public relations." An insurance industry spokesman acknowledged that sick people can have trouble buying insurance on their own but said the analysis overstates the problem.

The study found that one-fifth to one-half of non-elderly people in the United States have ailments that trigger rejection or higher prices in the individual insurance market. They range from cancer to chronic illnesses such as heart disease, asthma and high blood pressure.

The smaller estimate, by Health and Human Services Department researchers, is based on the number of Americans whose medical problems would make them eligible for states' high-risk pools - special coverage for people denied insurance because of their medical history. The researchers arrived at the larger figure by adding in other ailments that major insurers consider a basis to charge customers higher prices or to exclude coverage for some of the care they need.

Using those two definitions, the study took 2008 findings, the most recent available, from a large federal survey of medical expenditures to figure out how many people had reported that they were bothered by those health problems, had visited a doctor for them or had been at least temporarily disabled because of them.

The study is laced with reminders about provisions of the 2010 Patient Protection and Affordable Care Act - as the health-care law is formally known - that are designed to eliminate insurance problems for such people.

The most significant is scheduled to take effect in 2014, when the law will, for the first time, forbid insurers to charge sick patients more or reject sick applicants. Last year, two smaller changes took effect: a rule that insurers cannot reject sick children, and temporary subsidies until 2014 for a federal high-risk pool and new state ones. In their early months, the pools have not proved popular.

"Americans living with pre-existing conditions are being freed from discrimination in order to get the health coverage they need," HHS Secretary Kathleen Sebelius said in a statement. Repealing the law, she argued, would leave such people unprotected.